US-based clinical stage biopharmaceutical firm Epizyme has started a Phase Ib open-label clinical trial of EPZ-5676, a small molecule inhibitor of DOT1L, in paediatric patients with acute leukaemias bearing a rearrangement of the MLL gene (MLL-r).
The trial is designed to assess the safety, pharmacokinetics, and pharmacodynamics of escalating doses of EPZ-5676 in patients between the ages of three months and 18 years and to provide a preliminary assessment of efficacy.
In addition, Epizyme now has ongoing assessments of proof-of-concept (POC) in three genetically defined cancer patient groups in the EPZ-5676 clinical program (MLL-r adults, MLL-PTD, and MLL-r paediatrics) with data expected to be reported in the second half of this year.
Epizyme chief medical officer Eric Hedrick said acute leukaemias with MLL-r affect young children and are one of the last remaining forms of childhood leukaemia with inadequate treatment options.
"Children who are afflicted with this genetically defined cancer have an extremely poor prognosis, especially in comparison to pediatric leukemias without the MLL rearrangement," Hedrick said.
"This pediatric clinical study of EPZ-5676 is an important complement to our ongoing adult studies and reflects our commitment to developing personalized treatments for patients with genetically defined cancers."
The company is currently enrolling adult MLL-r and MLL-PTD acute leukaemia patients in the expansion stage of the adult EPZ-5676 Phase I trial.
Leukemia & Lymphoma Society chief scientific officer Lee Greenberger said while there has been progress in improving outcomes for paediatric patients with acute leukaemia, patients with MLL-r, a genetically defined leukaemia, still present a considerable challenge and a significant area of unmet need.
"We invested in the pre-clinical development of Epizyme's DOT1L inhibitor and applaud Epizyme's efforts as they develop targeted therapies to treat leukemia patients of all ages," Greenberger said.
In January, the company achieved a $25m clinical proof-of-concept milestone in their Celgene collaboration with objective responses observed in two adult MLL-r patients in the fourth cohort of the dose escalation stage of the Phase I trial, which completed enrolment in December 2013.
The company intends to release data from the adult Phase I dose escalation and expansion stage trial for EPZ-5676 in the second half of 2014.
EPZ-5676 is being developed for the treatment of patients with acute leukaemia in which the MLL gene is rearranged due to a chromosomal translocation (MLL-r) or partial tandem duplication (MLL-PTD).
The US Food and Drug Administration (FDA) and the European Commission have granted orphan drug designation to EPZ-5676 for the treatment of acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML).
Image: Bone marrow aspirate showing acute myeloid leukemia. Photo: courtesy of VashiDonsk.